Develop a numerical model of the Glymphatic system to investigate the flow patterns and transport processes

The brain is considered the body's most important organ, and the clearance of waste products from the brain is of vital importance. In the past, it was believed that the brain had no efficient disposal system due to its lack of lymphatic vessels. Also, it was thought that the only phenomenon in the brain is diffusion, and substances transportation was purely dependent on it. But not long ago, the ideas about the disposal system and brain phenomena were challenged after the rediscovery of the Glymphatic system. In this research, using the porous fluid-solid interaction approach, the Glymphatic system and the factors affecting its functioning have been investigated. The findings indicate that the increase in wall displacement does not cause significant changes in the volume exchange fraction of the perivascular space. Moreover, the reduction of displacement leads to a corresponding decrease in velocity magnitude in the perivascular spaces, which makes the conditions favorable for waste products to settle. Another finding of this research is that the wall oscillations are more effective in the paths adjacent to thicker ducts compared to the paths adjacent to narrower ducts so that the increase in wall oscillations causes an increase of 4.38 and 1.73 times respectively in the mentioned paths, which indicates that the influence of these oscillations is fading in the paths adjacent to narrower channels. Based on the results, the perivascular pathways have the ability to experience the Péclet number greater than one, which means that diffusion is not the only phenomenon in the brain. But in the porous tissue of the brain, the Péclet number still has smaller values than one.